It's not always fair. You want to take everything into consideration. But there are certain things that - on occasion, anyway - can have a disproportionate effect on your evaluation of a movie. Sometimes it's one great scene - a scene so great it lifts up those mixed feelings you were having and makes it all worthwhile.

Or perhaps more often, it's the ending - it's either so good it elevates everything that came before it, or so bad it ruins what might otherwise have been a pretty good movie.

Or in the case of Gerald's Game, it is both of those things. Which leaves us - me and the film, that is - at an impasse. It contains a scene - which takes place after considerable, if often frustrating and monotonous, build-up - that is among the most memorable and most technically impressive I have seen all year. It is a scene that singlehandedly - and I mean that literally - establishes the film's horror bonafides. It cannot be forgotten. Those who have difficulty watching replays of particularly gruesome sports injuries will be cringing during pretty much the entire sequence, and at its pivotal moment - if they're still watching - they will recoil in horror. Since we're on the subject of Stephen King adaptations, I'll put it like this: the scene I'm referring to in Gerald's Game makes the ankle/sledgehammer scene from Misery look like the surprised kitty video by comparison.

It's not just that it's the best scene in the film, or that it's a moment of simultaneous catharsis and revulsion. It's that it justifies and pays off the entire narrative conceit. It is a pure, nauseating, delirious delight. I applauded, alone on my couch.

But then there's that other thing. That ending. With respect to the difficulties of adaptation - in this case, adapting a 480-page novel built on internal monologues, subsconscious projections, imaginary friends and jumbo-sized symbolism - the ending that director Mike Flanagan and co-writer Jeff Howard choose to transfer from page to screen is a disaster. At least in movie form, anyway. Without, again, spilling the details, the ending inexplicably transforms a symbolic gesture into literal form, and all for what amounts to an extended coda. Referring to it as an "ending" is kind of a misnomer. It's merely an epilogue - the time-jumping follow-up to the film's climax - but an unusually long one (10-12 minutes? 15?) for a 103-minute feature. It's meant to provide a certain emotional and thematic closure, and perhaps Flanagan felt this particular sense of resolution was important.

He was incorrect. Instead of resolution, he gives us a wild left turn that does, yes, reframe certain aspects of the story we spent the previous 90 minutes watching, but without any new depths or insights. The literalization would almost be funny, in a meta sort of way, if it weren't so earnestly trying to double down on the symbolism it had firmly established already. That the film is propelled almost entirely by its central character's actions - physical acts, physical choices - has already gotten across what the concluding moments go out of their way to express.

Contained to a written medium, this all works a bit better - in theory, anyway. One literary device simply transforms into another; ultimately it all stays on the page. The same logic technically applies to a film - it's using the same devices, at least - but the effect of seeing something play out is a vastly different experience. It's a leap from one dimension to another. (Exhibit #73,488 why fidelity to source material is an irrelevant metric.)

The effectiveness of a movie can shift so fluidly. From scene to scene, subplot to subplot, shot to shot, even from one side of a conversation to another. Which is a roundabout way of saying Gerald's Game, like many difficult adaptations (and indeed many difficult conceptual experiments in general), ebbs and flows wildly, at times feeling like a missed opportunity and at others feeling like Flanagan has pulled off a miracle.

He certainly doesn't try to make things easy on himself, so give him credit for taking on the challenge of a movie whose protagonist is handcuffed to a bed nearly the whole time. Jessie (Carla Gugino) and her husband Gerald (Bruce Greenwood) were simply trying to spice up their sex life in a weekend getaway at their quiet vacation home. It doesn't take, exactly. What Gerald has in mind crosses a line Jessie neither accepts nor appreciates. Kinky fun turns to surprise turns to discomfort turns to anger and humiliation. (There are no flashbacks or digressions detailing the couple's relationship, so it's a testament to Greenwood's quiet greatness as an actor that in the moments during and after his character crossing a particular line, we see in him both the man Jessie knows so well and a new version that's just revealed itself. He is simultaneously familiar and unfamiliar.)

Then Gerald dies. Seizes up right there on the bed and collapses to the floor. The key to the handcuffs - locking Jessie's wrists to the bedposts - are out of range. No one in the neighborhood is around. It's the off-season, apparently. There's a dog roaming around outside but that's about it. Somehow Jessie has to either get herself out of this jam, or survive long enough for someone else to show up (not expected for at least a few days).

The initial humor of the situation is somewhat lost on Flanagan (or at least he doesn't know exactly what to do with it). Agreeing to a little bit of light bondage only for your lover to die in the middle of it is a scenario straight out of a nightmare comedy. And so it makes sense that the scenario, as it plays out over hours and days, takes place largely within her head. She's joined by others - versions of herself, versions of Gerald - as she tries to figure out how to escape or survive, or understand what she is or is not capable of. The film becomes an extended "angel on one shoulder, devil on the other" situation, her projected self trying to access Jessie's hidden reserves of strength, the projected Gerald attempting to belittle or taunt her. Turns out an unexpected fight for survival can turn into quite the intensive therapy session.

But what amounts to constant running commentary of the situation at hand gets pretty old pretty quickly; Flanagan's shifting camera angles work nicely early on, with Jessie's two imaginary friends coming at her from different directions and distances, the scales constantly tipping this way or that. But there's a redundancy to the filmmaking that is hard to avoid after a while. The otherwise straightforward nature of Flanagan's aesthetic begins to actively work against this would-be psychological thriller. His images do nothing to get into Jessie's frame of mind; visually there is no sense of claustrophobia or panic. The matter-of-fact approach can't sustain the narrative. This is a hard criticism to describe, but it's a flaw that's all too common - filmmakers who know how to deftly stage action but have no ability to establish a psyche, to express psychological point of view.

Then again, it's not every movie that's able to pull off what happens at about the 80-minute mark of Gerald's Game. This is one of those odd instances of a film that doesn't necessarily work, but which - for a specific reason or two - is well worth sitting through anyway. We'll call it a draw.